Commit ea0371f7 authored Mar 04, 2019 by Peter Oskolkov Committed by Daniel Borkmann Mar 07, 2019

net: fix GSO in bpf_lwt_push_ip_encap



GSO needs inner headers and inner protocol set properly to work.

skb->inner_mac_header: skb_reset_inner_headers() assigns the current
mac header value to inner_mac_header; but it is not set at the point,
so we need to call skb_reset_inner_mac_header, otherwise gre_gso_segment
fails: it does

    int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
    ...
    if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
    ...

skb->inner_protocol should also be correctly set.

Fixes: ca78801a ("bpf: handle GSO in bpf_lwt_push_encap")
Signed-off-by: Peter Oskolkov <posk@google.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 915905f8

net/core/lwt_bpf.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -625,6 +625,8 @@ int bpf_lwt_push_ip_encap(struct sk_buff skb, void hdr, u32 len, bool ingress)

		/* push the encap headers and fix pointers */
		skb_reset_inner_headers(skb);
		skb_reset_inner_mac_header(skb); /* mac header is not yet set */
		skb_set_inner_protocol(skb, skb->protocol);
		skb->encapsulation = 1;
		skb_push(skb, len);
		if (ingress)

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